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YAML

Introduction

• YAML Ain’t Markup Language.
• Human-readable alternative to JSON.
• Indentation is very key. (like Python)
• Used for configuration, not for programming logic.

Key Principles

• Whitespace indentation -> hierarchy
• Colon (:) -> Key Value Pair
• Dash (-) -> List Item
• Comments (#)

Use Cases in MLOps

• MLflow experiment configs (parameters, environments)
• Kubernetes -> Pods, Services, Deployments
• Docker Compose -> multi-container setups
• CI/CD pipelines -> GitHub Actions, GitLab CI, Azure DevOps

{
  "experiment": "CO2_Regression",
  "params": {
    "alpha": 0.1,
    "max_iter": 100
  },
  "tags": ["linear_regression", "mlflow"]
}

experiment: CO2_Regression
params:
  alpha: 0.1
  max_iter: 100
tags:
  - linear_regression
  - mlflow

YAMLLint OR VSCode YAML Validator Extension

YAML Data Structures

Scalars (strings, numbers, booleans)

learning_rate: 0.01
early_stopping: true
experiment_name: "CO2_Prediction"

Lists

models:
  - linear_regression
  - random_forest
  - xgboost

Dictionaries (maps)

params:
  n_estimators: 100
  max_depth: 5

Description

description: |
  This is a multi-line string.
  It preserves line breaks.
  Useful for comments/description/notes.

Putting together

experiment:
  name: CO2_Regression
  params:
    alpha: 0.1
    max_iter: 100
  metrics:
    - mse
    - r2
  description: |
    Model built using Linear Regression.
    We can use univariate or multi variate.

  environments:
    development:
      database: sqlite
    production:
      database: mysql

Default Values Using &anchorName and *anchorName and Merge Key <<

base_config: &base
  host: localhost
  port: 3306

development:
  <<: *base
  database: dev_db

production:
  <<: *base
  database: prod_db
  host: prod.server.com

Using Environment Variables

config:
  path: ${USERPROFILE}\folder1

Mac/Linux/Git Bash

export USERPROFILE="sometext"

Command Prompt

set USERPROFILE="sometext"

YAML Variables

variables:
  base_url: http://example.com
endpoints:
  user: ${variables.base_url}/user
  admin: ${variables.base_url}/admin

https://github.com/gchandra10/python_yaml_demo.git

#yaml #json #pythonVer 0.3.6